ellis@spar.UUCP (Michael Ellis) (10/04/85)
>> Rich, your own words answer your questions elsewhere: >> your knowledge of what blue looks like is subjective knowledge. >> It certainly isn't objective, and it certainly isn't mere belief. >> This "feeling" of blueness is not explainable mechanically. >> You may mess around in the brain and note when the feeling happens, >> but you won't find the feeling itself. That is located only within your >> personal experience. Before you start devising a response, think about >> whether you have a vested interest in contradicting what I have said. >> Is your response obvious, or do you have to hunt for it? [BALTER] > >Very obvious, because I happen to agree with what you said (up to the point >where you seems to assume that I would disagree with you). Except the words >"subjective knowledge" are perhaps inappropriate. The feeling of blueness >is indeed explainable "mechanically": it is the sensation produced by >blue light (light of specific wavelengths). [RICH] I think you missed the point, Rich... "There is not even any common property possessed by all sweet, rough, "or red things. A grey surface looks red if we have been looking at a "blue-green one; plain paper feels smooth if we have been feeling "sandpaper or rough if we have been feeling plate glass; and tap "water tastes sweet if we have been eating artichokes. - B.F. Skinner What we call color transcends `specific wavelengths', or even responses caused by (as in the Skinner quote) presenting the senses with new stimuli that contrast with old ones to which one has become acclimated. Subjective color sensations are modified by surrounding colors, by the intensity (not to mention the color) of illumination, by the texture, reflectivity, luminescence, etc.. of the object, and even by motion -- spinning white disks with appropriately placed black marks are sometimes seen to have color. Analysis of color into primaries yields even more enigmatic results. The same subjective experience of yellow, for example, is not only produced by pure radiation in the yellow frequency range, there are also an infinity of combinations of reds and greens that work as well. And a mysterious segment in the circle of pure, fully saturated colors -- the purples -- corresponds to no frequency whatsoever. The lowest reds are not the same as the highest violets.. A great deal of work has been done to produce a machine that can simulate human color differentiation (which varies by culture as well as by individual), but one thing is clear -- what we call color does not really exist, objectively. Color is an illusion produced by human nature that identifies many differing physical phenomena into a single subjective experience we call `red',`green', etc. The subjective experience of blue is not knowledge that a genuine blue object is out there in the real world. The subjective experience of blue is a fact in-itself. -michael The great change so long awaited had finally taken place. On the earth there was air, and water. And over that newborn blue sea, the sun - also colored - was setting, an absolutely different and even more violent color.. How red the sun is.." -Italo Calvino (I heard he died in the past week, BTW)